JPH07103151A - Scroll type hydraulic machine - Google Patents

Abstract

PURPOSE:To stabilize the behavior of a turning scroll by reducing the extent of thrust load and torsional moment acting on the turning scroll. CONSTITUTION:A turning scroll 21 is turnably installed in space between both first and second fixed scrolls 2 and 3, and an auxiliary crank 11 preventing a rotation of the turning scroll 21 and a driving shaft 13 are rotatably installed each in booth supporting parts 9 and 10 of these fixed scrolls 2 and 3 via each of bearings 14, 15 and 16 or the like, while the turning scroll 21 is made to do its turning motion to these fixed scrolls 2 and 3 at a turning radius, say, size (e). With this turning motion, each compression space 30 between two lap parts 7 and 23 and each compression space 31 between other two lap parts 8 and 24 are all continuously reduced, whereby air inhaled from each of inlet ports 32 and 33 is discharged toward an air tank at the outside from two discharge ports 34 and 35 as compressing it in order in these compression spaces 30 and 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid machine suitable for use in, for example, an air compressor or a vacuum pump.

[0002]

2. Description of the Related Art Generally, a casing, a fixed scroll which constitutes a part of the casing, and has a spiral wrap portion formed on a mirror plate, a base end side of which is rotatably supported by the casing, and a tip end side of which is the casing. A drive shaft, which is a crank shaft extending inward, is rotatably attached to the crank shaft of the drive shaft, and is spirally attached to the end plate so as to define a plurality of compression chambers between the drive shaft and the wrap portion of the fixed scroll. The orbiting scroll in which the wrap portion of is formed, and provided between the orbiting scroll and the casing (fixed scroll),
A rotation prevention mechanism that prevents the orbiting scroll from rotating, a suction port formed in the casing (fixed scroll) so as to communicate with the outermost compression chamber of the compression chambers, and the compression units. There is known a scroll fluid machine including a discharge port formed in the fixed scroll so as to communicate with the innermost compression chamber of the chambers.

In this type of conventional scroll type fluid machine, for example, when used as an air compressor, the base end side of the drive shaft is rotationally driven from the outside of the casing by a drive source such as a motor, and the drive shaft is rotated. Is transmitted to the orbiting scroll via the crankshaft and the orbiting scroll is prevented from rotating by the rotation preventing mechanism, whereby the orbiting scroll is caused to orbit with a fixed orbiting radius with respect to the fixed scroll. The plurality of compression chambers formed between the wrap portion of the fixed scroll and the wrap portion of the orbiting scroll are compressed from the suction port to the outermost peripheral side compression chamber while being gradually reduced by the orbiting motion of the orbiting scroll. While sequentially compressing the sucked air, the compressed air is discharged from the innermost circumferential compression chamber toward the external air tank or the like via the discharge port.

[0004]

In the prior art described above, the orbiting scroll is rotatably mounted on the crankshaft of the drive shaft extending in the casing in a cantilevered state, and the orbiting scroll is prevented from rotating by the rotation preventing mechanism. However, since the orbiting scroll is configured to orbit with respect to the fixed scroll with a certain orbiting radius, a large load acts on the orbiting scroll in a cantilevered supported state in a large scroll fluid machine or the like, and the orbiting scroll and There is a problem that the bearing of the drive shaft is easily worn and damaged early and the life cannot be improved.

Further, since each compression chamber formed between the lap portion of the fixed scroll and the orbiting scroll is gradually reduced by the orbiting motion of the orbiting scroll, fluid such as air is compressed in each compression chamber. At this time, the orbiting scroll receives a large reaction force. That is, since the so-called thrust load and torsional moment (so-called overturning moment) act on the orbiting scroll in the direction of separating from the fixed scroll, it is necessary to provide a thrust bearing for supporting these between the orbiting scroll and the casing. However, there is a problem that it takes a lot of time and labor to process the thrust bearing and the workability during manufacturing cannot be improved.

On the other hand, in order to solve the above-mentioned problem, the applicant of the present invention has previously proposed in Japanese Patent Application No. Sho 63-109450 (hereinafter referred to as other prior art) that two orbiting scrolls are provided facing each other in a casing. A scroll-type fluid machine configured to compress a fluid such as air by gradually reducing the compression chambers formed between the wrap portions of the orbiting scrolls by causing the orbiting scrolls to perform a relative orbiting motion. Proposed. Further, in this case, a large load is not applied to the bearing and the like, it is possible to cope with a large-sized model, and the load in the thrust direction can be offset between the orbiting scrolls. There is an advantage that the load on the etc. can be reduced.

However, in the other prior art, it is necessary to drive the orbiting scrolls in synchronism with each other, the behavior at the time of starting becomes unstable, and a relatively large thrust direction is provided between the wrap portions of the orbiting scrolls. Since it is necessary to form a gap to absorb the thermal expansion of each wrap, the compressed fluid inside will easily leak through this gap, and stability and reliability during compression operation etc. will be improved. There is a problem that it cannot always be improved.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can effectively reduce the thrust load and the torsion moment acting on the orbiting scroll, and can significantly reduce the load on the bearing and the like. Moreover, it is an object of the present invention to provide a scroll type fluid machine capable of stabilizing the behavior of an orbiting scroll and improving reliability.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to first and second devices which are axially separated from each other and face each other, and each end plate has a spiral wrap portion. Of the fixed scroll and the fixed scrolls are rotatably provided, and each of the fixed scrolls has a spiral shape so as to define a plurality of compression chambers between the fixed scroll and each of the fixed scrolls. Of the orbiting scroll in which the wrap portion is formed, a rotation preventing mechanism that is provided between the orbiting scroll and the fixed scroll, and prevents the orbiting scroll from rotating, and the outermost peripheral side of the compression chambers. The first and second suction ports formed in the first and second fixed scrolls so as to communicate with the compression chambers and the compression chambers on the innermost peripheral side among the compression chambers are communicated with each other. First,
The structure including the first and second discharge ports formed in the second fixed scroll is adopted.

Further, the wrap portions of the orbiting scroll have the same orbiting radius, tooth thickness and tooth height, and the wrap angle of one wrap portion from the winding start end to the winding end end is equal to the vortex angle of the other wrap portion. It is preferable to form it so that it is smaller by a very small amount.

[0011]

With the above construction, when the orbiting scroll is orbitally moved between the first and second fixed scrolls, the orbiting scroll has wrap portions formed on both axial side surfaces of the end plate with the wrap portions of the respective fixed scrolls. While gradually shrinking each compression chamber between, the fluid sucked into the compression chambers on the outermost peripheral side from the first and second suction ports is sequentially compressed,
The compressed fluid is discharged from the innermost compression chambers to the outside via the first and second discharge ports. Then, the end plate and each wrap portion of the orbiting scroll receive the thrust load and the torsion moment in the opposite directions from the compression chambers on both sides in the axial direction, so that these thrust load and the torsion moment are canceled out. It is possible to stabilize the orbiting motion of the orbiting scroll.

If one of the wrap portions of the orbiting scroll is formed so that the spiral angle is smaller than that of the other wrap portion by a very small amount, the end plate of the orbiting scroll is provided on both sides in the axial direction. The orbiting scroll can be continuously pushed toward one of the first and second fixed scrolls with a small pressing force without completely canceling out the thrust load acting from the compression chamber. It is possible to prevent the gap from changing and stabilize the behavior of the orbiting scroll.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A scroll fluid machine according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5 by using a scroll type air compressor as an example.

In the figure, 1 is a casing of an air compressor, 2 and 3 are first and second fixed scrolls which constitute the casing 1 together with a spacer 4, and the fixed scrolls 2 and 3 are as shown in FIG. Disk-shaped mirror plates 5 and 6 which are axially opposed to each other via a spacer 4 and have their centers aligned with each other, and are installed upright on the surfaces of the mirror plates 5 and 6 facing each other, respectively, and the involute Alternatively, the wrap portions 7 and 8 formed in a spiral shape with a curve close to an involute, and the support formed on the outer peripheral side of the end plates 5 and 6 so as to surround the wrap portions 7 and 8 from the outside in the radial direction. 1 and the supporting portions 9 and 10 are shown in FIG.
It has a substantially triangular framework structure as shown in.

Here, the support portions 9 and 10 of the fixed scrolls 2 and 3 are provided with auxiliary cranks 11 and 12 which are separated by an angular interval of, for example, about 120 degrees and serve as a rotation preventing mechanism for the orbiting scroll 21 described later. A drive shaft 13 is rotatably provided via bearings 14, 14, 15, 16 and the like, and the drive shaft 13 is rotationally driven from the outside of the casing 1 by a drive source (not shown) such as a motor. And
The crankshaft 13A of the drive shaft 13 and the auxiliary crank 1
The crankshafts 11A of 1 and 12 are eccentrically formed by a dimension e as shown in FIG.
It makes a turning motion with a turning radius.

Further, the end plates 5, 6 of the fixed scrolls 2, 3
The casing 1 from the surface opposite to the wraps 7 and 8.
A large number of cooling fins 17, 17, ...
18 are integrally formed, and each cooling fin 17,
The projecting side end surface of 18 is covered with flat plate-shaped covers 19 and 20 that form cooling air passages between the cooling fins 17 and 18, respectively. A plurality of cooling air passages (not shown) are also formed in the spacer 4 so that cooling air can flow between the cooling fins 22C of the orbiting scroll 21 described later.

Reference numeral 21 denotes an orbiting scroll which is rotatably disposed between the fixed scrolls 2 and 3, and the orbiting scroll 21 is formed in a disk shape on both axial sides as shown in FIGS. 2 to 5. End plates 22A, 22B, and a large number of cooling fins 22C, 22 are provided between the end plates 22A, 22B.
End plate 22 in which C, ... Are lined up, and end plate part 2 of the end plate 22.
2A, 22B surface to fixed scroll 2, 3 end plate 5,
The wrap portion 2 which is erected upright toward the scroll scroll 6 and is spirally formed in correspondence with the wrap portions 7 and 8 of the fixed scrolls 2 and 3 with an involute or a curve close to the involute.
3 and 24, and three projecting portions 25, 26, and 27 projecting radially outward from the outer peripheral side of the end plate 22.

Here, the overhanging portions 25, 26, 27 of the orbiting scroll 21 are, for example, 1 as shown in FIGS.
They are arranged on the outer peripheral side of the end plate 22 with an angular interval of about 20 degrees. Then, the orbiting scroll 21 is the overhanging portion 2
5, 26 and 27 are crankshafts 1 of the auxiliary crank 11
1A, a crankshaft (not shown) of the auxiliary crank 12, and a crankshaft 13A of the drive shaft 13 have swivel bearings 28,
When the drive shaft 13 is rotatably supported via 29 or the like, the auxiliary cranks 11 and 12 prevent rotation, and a turning motion having a turning radius of the dimension e is given. In addition, in FIG. 3, the end plate portion 22A of the end plate 22 is
22B, each cooling fin 22C, and the wrap portions 23, 24
The overhang portions 25, 26, and 27 are omitted for the sake of clarity.

Further, the wrap portion 2 of the orbiting scroll 21.
3 and 24 are arranged so as to be overlapped with the wrap portions 7 and 8 of the fixed scrolls 2 and 3 by shifting a predetermined angle in the circumferential direction, and the orbiting scroll 21 is fixed to the fixed scrolls 2 and 3.
Is eccentric by the dimension e. As a result, when the orbiting scroll 21 is orbited with respect to the fixed scrolls 2 and 3, the wrap portions 7 and 2 facing each other are provided.
The first compression chambers 30, 30, ... and the second compression chambers 31, 3 whose volumes are continuously reduced between the space 3 and the lap portions 8 and 24.
1, ... are defined.

Further, the wrap portion 2 of the orbiting scroll 21.
3 and 24 have the same turning radius, tooth thickness, tooth height, etc., as shown in FIGS. 3 to 5, but the wrap portions 23 and 24 have opposite spiral directions. Then, the wrap portion 23 located on the compression chamber 30 side has a vortex angle from the winding start end to the winding end end that is slightly smaller than the vortex angle of the wrap portion 24 located on the compression chamber 31 side, for example, for a reason to be described later. It is formed so as to be smaller by a small angle c of about 3 to 10 degrees.

Reference numerals 32 and 33 denote first and second suction ports provided in the fixed scrolls 2 and 3, reference numerals 34 and 35 denote first and second discharge ports, and the suction ports 32 and 33 are on the outermost peripheral side. Are arranged on the outer peripheral sides of the end plates 5 and 6 so as to communicate with the compression chambers 30 and 31, and the discharge ports 34 and 35 are located at the centers of the end plates 5 and 6 so as to communicate with the compression chambers 30 and 31 on the innermost peripheral side. Is disposed in the section. Here, the diameter of the discharge port 35 communicating with the compression chamber 31 on the innermost peripheral side is equal to that of the compression chamber 30 on the innermost peripheral side.
Is formed to have a diameter larger than the diameter of the discharge port 34 communicating with the orbiting scroll 34, and stabilizes the behavior of the orbiting scroll 21. The discharge ports 34, 35 are connected to an external air tank (not shown) or the like via an air pipe, and the discharge ports 34, 35 are in communication with each other via an air pipe or the like.

Further, reference numerals 36, 36, ..., 37 denote balance weights provided at both axial ends of the auxiliary cranks 11, 12 and the drive shaft 13, respectively, and the balance weights 36, 37 respectively make the orbiting movement of the orbiting scroll 21. The balance weight 37 of the drive shaft 13 also functions as a flywheel for stabilizing the rotation of the drive shaft 13.

The scroll type air compressor according to this embodiment has the above-mentioned construction, and its operation will be described below.

First, when the drive shaft 13 is rotationally driven from the outside of the casing 1 by a drive source (not shown) such as a motor, this rotation is performed from the crankshaft 13A of the drive shaft 13 through the orbiting bearing 29 and the like to orbit scroll. I was told to 21
The orbiting scroll 21 is prevented from rotating by the auxiliary cranks 11 and 12, and the crankshaft 13A of the drive shaft 13 is prevented.
As a result, a turning motion having a turning radius of dimension e is performed.

By this swiveling motion, the compression chambers 30 between the lap portions 7 and 23 and the compression chambers 31 between the lap portions 8 and 24 are continuously reduced, and the suction port 3
The air sucked from 2, 33 is compressed in each compression chamber 30, 3.
This compressed air is compressed in the discharge port 3
Discharge from 4, 35 toward an external air tank or the like. At this time, the discharge ports 34 and 35 are communicated with each other via an air pipe or the like, and are in the same pressure state.

Here, thrust forces f1 and f2 as so-called thrust loads and twisting forces f3 and f4 as torsion moments (so-called overturning moments) act on the orbiting scroll 21 in the direction in which it separates from the fixed scrolls 2 and 3. To do.

The pressure acting on the end plate portion 22A of the orbiting scroll 21 from each of the first compression chambers 30 is defined as P1.
Assuming that each pressure receiving area of the end plate portion 22A that receives these pressures P1 is S1, the thrust force f1 acting on the end plate portion 22A is

[0028]

## EQU1 ## It is obtained as f1 = .SIGMA.P1.times.S1.

If the pressure acting on the end plate portion 22B of the orbiting scroll 21 from the second compression chambers 31 is P2, and the pressure receiving area of each end plate portion 22B that receives these pressures P2 is S2, the end plate portion will be described. The thrust force f2 acting on 22B is

[0030]

## EQU2 ## It is obtained as f2 = .SIGMA.P2.times.S2.

These thrust forces f1 and f2 act on the orbiting scroll 21 in directions opposite to each other, and the wrap portions 23 and 24 of the orbiting scroll 21 have substantially the same spiral direction, although they are in opposite directions. Since it is formed in the lap shape, it is possible to cancel the thrust forces f1 and f2.

Next, the wrap portion 2 of the orbiting scroll 21.
Torsional force f3 as a torsional moment acting on 3, 24
, F4 will be examined.

First, the pressure acting on the wrap portion 23 of the orbiting scroll 21 from each first compression chamber 30 is set to P3, the pressure receiving area of each lap portion 23 for receiving these pressures P3 is set to S3, and the end plate portion If the outer diameter of 22A is D and the distance from the center of gravity G of the orbiting scroll 21 to the center of gravity of the wrap portion 23 is L, the twisting force f3 acting on the wrap portion 23 is

[0034]

[Equation 3] f3 = L × (ΣP3 × S3) ÷ (D / 2)

The pressure acting on the lap portion 24 of the orbiting scroll 21 from each of the second compression chambers 31 is P4, and the pressure receiving area of each lap portion 24 that receives these pressures P4 is S4. If the outer diameter of 22B is D and the distance from the center of gravity G of the orbiting scroll 21 to the center of gravity of the wrap portion 24 is L, the twisting force f4 acting on the lap portion 24 is

[0036]

[Equation 4] f4 = L × (ΣP4 × S4) ÷ (D / 2)

These twisting forces f3 and f4 act on the orbiting scroll 21 as mutually opposite forces, and although the wrap portions 23 and 24 of the orbiting scroll 21 have spiral directions opposite to each other, they are substantially Since they are formed in the same lap shape, it is possible to cancel the twisting forces f3 and f4.

However, in the actual production of the air compressor, it is necessary that the wrap portions 7 and 8 of the fixed scrolls 2 and 3 and the wrap portions 23 and 24 of the orbiting scroll 21 have some dimensional tolerance. Therefore, it is very difficult in practice to completely cancel the thrust forces f1 and f2 and the twisting forces f3 and f4.

Therefore, in this embodiment, the orbiting scroll 2 is used.
The wrap portions 23, 24 of No. 1 are formed so that the turning radius, tooth thickness, tooth height, etc. are the same as shown in FIGS.
The wrap portion 23 located on the compression chamber 30 side has a vortex angle from the winding start end to the winding end end that is slightly smaller than the vortex angle of the wrap portion 24 located on the compression chamber 31 side.
It is formed so as to be reduced by a minute angle c of about 0 degree.

As a result, in the orbiting scroll 21, the thrust force f1 from the compression chamber 30 side is slightly smaller than the thrust force f2 from the compression chamber 31 side, and the twisting force f3 acting on the wrap portion 23 side is the lap portion 24 side. It is slightly smaller than the twisting force f4 of. In this case, the discharge ports 34, 35
The positions may be shifted from each other by a minute angle c, and by changing the diameters of the discharge ports 34 and 35, the same effect as the above can be obtained.

Therefore, according to this embodiment, the wrap portion 23 of the orbiting scroll 21 can be constantly pressed toward the end plate 5 side of the fixed scroll 2 during the compression operation of the air compressor, and the wrap portion 23 It is possible to effectively prevent the gap in the thrust direction from changing between the tip (tooth tip) and the surface (tooth bottom) of the end plate 5, and the orbiting motion of the orbiting scroll 21 causes the thrust forces f1, f2 and torsion. It is possible to reliably prevent instability due to the influence of the forces f3, f4 (torsion moment), etc., and it is possible to greatly stabilize the behavior of the orbiting scroll 21.

Further, since the thrust forces f1 and f2 generated during the orbiting operation of the orbiting scroll 21 can be substantially offset and the torsional forces f3 and f4 can also be substantially offset, the orbiting scroll 21 is acted. Thrust load, torsional moment, etc. can be effectively reduced, and loads on the bearings 14, 15, 16 and the slewing bearings 28, 29, etc. can be significantly reduced. Then, these bearing loads can be comfortably reduced, and durability and reliability can be effectively improved.

Further, the pressure balance between the compression chambers 30 and 31 can be reasonably stabilized, and even when applied to a large air compressor, the operation performance as a compressor can be reliably stabilized. In addition, various effects can be obtained such that reliability can be improved.

In the above embodiment, a scroll type air compressor has been described as an example of the scroll type fluid machine, but the present invention is not limited to this, and for example, a scroll type vacuum pump or a compressor for a refrigerant. It can also be widely applied to

[0045]

As described above in detail, according to the present invention, an orbiting scroll is rotatably provided between the first and second fixed scrolls, and the orbiting scroll is provided between the fixed scroll and the wrap portion of each fixed scroll. Since the spiral wraps are formed on both axial side surfaces of the end plate so as to respectively define a plurality of compression chambers, the end plate and each wrap part of the orbiting scroll are separated from the compression chambers on both axial sides. The thrust load and the torsion moment in the directions opposite to each other are received, these thrust load and the torsion moment can be canceled, and the orbiting motion of the orbiting scroll can be stabilized. Therefore, the load on the bearing and the like can be significantly reduced, the behavior of the orbiting scroll can be stabilized, and the operating performance and reliability can be significantly improved.

If one of the wrap portions of the orbiting scroll is formed so that the spiral angle from the winding start end to the winding end end is smaller than that of the other wrap portion by a very small amount, The orbiting scroll can be continuously pressed toward one of the first and second fixed scrolls with a small pressing force, suppressing the change in the thrust gap and stabilizing the behavior of the orbiting scroll. Therefore, the reliability and durability of the scroll fluid machine can be significantly improved.

[Brief description of drawings]

FIG. 1 is an external view showing a scroll type air compressor according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged perspective view of a main part of the orbiting scroll shown in FIG.

FIG. 4 is a front view of the orbiting scroll shown in FIG.

FIG. 5 is a rear view of the orbiting scroll shown in FIG.

[Explanation of symbols]

 1 Casing 2,3 Fixed scroll 4 Spacer 5,6,22 End plate 7,8,23,24 Lap part 11,12 Auxiliary crank (rotation preventing mechanism) 11A, 13A Crankshaft 13 Drive shaft 14,15,16 Bearing 21 Swing Scroll 22A, 22B End plate 30, 31 Compression chamber 32, 33 Suction port 34, 35 Discharge port c Micro angle (micro amount) e Dimension (gyration radius)

Claims (2)

[Claims] 1. A first and a second device, which are axially separated from each other and are opposed to each other, and a spiral wrap portion is formed on each end plate.
Of the fixed scroll and the fixed scrolls are rotatably provided, and each of the fixed scrolls has a spiral shape so as to define a plurality of compression chambers between the fixed scroll and each of the fixed scrolls. Of the orbiting scroll in which the wrap portion is formed, a rotation preventing mechanism that is provided between the orbiting scroll and the fixed scroll, and prevents the orbiting scroll from rotating, and the outermost peripheral side of the compression chambers. The first and second suction ports formed in the first and second fixed scrolls so as to communicate with the compression chambers and the compression chambers on the innermost peripheral side among the compression chambers are communicated with each other. A scroll fluid machine comprising first and second fixed scrolls and first and second discharge ports. 2. The orbiting wraps of the orbiting scroll have the same orbiting radius, tooth thickness and tooth height, and the wrapping angle of one wrapping portion from the winding start end to the winding end end is the same as that of the other wrapping portion. The scroll type fluid machine according to claim 1, wherein the scroll type fluid machine is formed so as to be smaller than the above by a minute amount.